Improvement in drawing-boards



L. F. SCHWENKEL. l Improvement in Drawing Boards. No. 125,089, PatentedMarchZJSZ. 4 @tgl/l i ff l WWYWW wwmm.. .Q4/cbm. V

UNITED STATES LUDWIG SCHWENKEL, OF NEW YORK, N. Y.

IMPROVEMENT IN DRAWING-BOARDS.

Specification forming part of Letters Patent No. 125,089, datedMarch 26, 1872.

To all whom it may concern! Be it known that I, LUDWIG F. SCHWEN- KEL, of the city, county, and State of New York, have invented a new and useful Improvement in Drawing-Board; and I do hereby declare the following to be a full, clear, and exact description thereof, which will enable those skilled in the art to makel and use the same, reference being had to the accompanying drawing forming part of this specification, in which drawing- Figure l is an under-side plan view of my improvement. Fig. 2 is a longitudinal section taken in the plane of the line a' of Fig. l. Fig. 3 is a cross-section taken in the plane of the line y y of Fig. l, when the board is in a horizontal position. Fig. 4 is also a cross-section taken in the same plane y y when the board is in an inclined position. Fig. 5 is a cross-section through the middle of the draw' er inthe line z z of Fig. l.

Similar letters indicate corresponding parts.

This invention relates to drawing-boards; and consists of a board of wood or other suit-` able material having a smooth surface, such as is required for supporting paper or cloth in drawing or tracing, provided at its ends with nipping-rollers for nipping and holding the ends of the cloth or paper placed on the board so as to dispense with drawing-pins or tacks. The under side of thc apparatus is provided near its ends with permanent transverse cleats which support it, when it is intended to be flat or in the same plane as the surface of the table or desk on which it is laid, and alongside the cleats are placed bars, which are hinged or pivoted by one end to the cleats or to the under side of the apparatus, so that the other end is capable of swinging downward for the purpose of raising the apparatus to an inclined position. The swinging bars are locked to the cleats by a key, which enters holes `made through both, a-nd which holes coincide when the bars are closed. When the key is withdrawn the bars can be moved downward or outward from the under side of the apparatus, and they are held out at any required angle by means of a loose slide which is pushed along between them and the under side of the apparatus. This slide, though loose, is yet, when not in use, retained to the apparatus by means of hooks formed on the under side of the swinging bars near their ends, which hooks, being large enough to admit the slide, hold it to the apparatus, and the bars are allowed, when the slide lies in the hooks, to lie hat again st the under side of the apparatus, where they are locked by the key above mentioned.

The nipping-rollers in this example are made of India rubber, and are in pairs, and are so mounted as to press against each other sufficiently close to enable them to nip or seize the thinnest fabric presented at the angle where they come together. But l do not restrict myself to any particular material in the construction of the rollers or nipping devices, nor to their use in pairs. The nipping devices may be made of a single elastic roller at the end, working against a iiXed surface, and a clamp may be used at one end ofthe drawingboard to hold one end of the sheet, and my nipping device applied at the other end, to seize the other end of the sheet and stretch it over the board. The shaft of one of the nipping-rollers at each end of the board projects a little distance, and is squared to enable it to be 0perated by a key, by which the roller can be turned to nip or release the cloth at pleasure. The under side of the apparatus at the front edge is provided with a tool-drawer, which is locked by means of a cam formed on the inner end of the shank of the knob, by which the drawer is moved in and out. The knob is so arranged that it can be turned on its axis, and, when its cam is turned toward the under side 'of the board it enters a groove made therein to receive it, and the drawer thereby becomes locked.

The letter A designates a ilat board, having a surface suitable for supporting paper or cloth in drawing. At its ends are arranged elastic rollers B B, arranged in pairs, Whose shafts turn in bearing-plates that project from the sides of the board. The rollers are arranged below the working surface of the board, one of each pair being placed under the edge of the board, so that the outer roller comes in contact with the inner roller under or nearly under the edge of the board. One roller of each pair has one end of its shaft projecting, as shown at G, through and beyond the bearing-plate which supports it, and such projecting end is squared to fit a key, D, by which the roller is turned either to nip and draw down the cloth or paper, or to release it. The letter E designates a sheet of tracing-cloth, which must be less in width than the length ot' the rollers, so as to allow the rollers to act on each other by frictional contact, so that the one that is turned by the key may impart its rotation to the other, and such sheet is held to the board by means of the rollers, its ends being held between the rollers of each pair with sufficient pressure to bring it smooth on the board. The rollers can be mounted in sliding bearings or boxes, .so that they can be tightened against each other by means of set-screws, in t-he ordinary manner of tightening pressure-rollers. The board A is provided with cleats F F. one across each end, within the rollers, which cleats strengthen the board and form a supporting surface for it. On the inner sides of the cleats F are arranged swinging-bars G G, which are each pivoted by one end to the adjacent cleat, as is represented at H I-I, in Figs. l and 4, the connection being made at those ends which are next the front edge ot the board, so that those ends of thel bars which extend toward the back edge shall be free to swing out away from the board when required. The bars are kept conlined to the cleats when they are t0 remain in their folded condition by means of a key, I, which passes through slots J made in the cleats and bars, as shown in the drawing. When the key is withdrawn the bars can be swung down, as is shown in Fig. 4, or the board bc raised up from the bars to an inclined position, and locked in that position by means of a locking slide, K, which is shoved along between the board and the bars as far as required. The slide K is provided with guides L L which project from its inner edge and move along inside of the bars so as to keep the slide in place, and the ends oli the slide, which move beneath the bars, are reduced so as to permit them to lie in recesses M M cut in the adjacent surfaces of the bars near their free ends, whereby the slide is not only locked fast when not in use, but the bars which hold it are allowed to lie flush with the cleats, in which position they are fastened by the key I. The letter N designates a drawer, which is arranged in the ordinary manner to slide in and out beneath the .board A at its front edge, and which is provided with a knob, O, that is free to turn on its axis. The inner end of the knob Within the drawer is provided with a cam, l?, which engages a groove, Q, made in the under surface of the board in such a manner that the drawer is locked by turning the knob.

What I claim as new, and desire to secure by Letters Patent, is

l. The combination, with a drawing-board, A, of elastic nipping-rollers B, substantially as and for the purpose described.

2. The pivoted bars G G for raising the board A, as described, in combination with a.

slide, K, having guides L to keep it in proper relation to the bars, substantially as described.

3. Ihe recesses M in the bars, arranged as described, in combination with the slide K, to hold it to the board when the slide is not in use, substantially as described.

4. The combination of the pivoted bars G, cleats F, and the key I, the key being passed through slots in the bars and cleats to lock them to each other, substantially as described.

This specification signed by me this 24th day of January, 1872.

LUDWIG F. SGHWENKEL.

Witnesses:

E. F. KASTENHUBER, Cialis. WAHLERs. 

